pwm: Mark free pwm IDs as used in alloc_pwms()

alloc_pwms() only identified a free range of IDs and this range was marked
as used only later by pwmchip_add(). Instead let alloc_pwms() already do
the marking (which makes the function actually allocating the range and so
justifies the function name). This way access to the allocated_pwms
bitfield is limited to two functions only.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-4-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -51,6 +51,8 @@ static int alloc_pwms(unsigned int count)
 	if (start + count > MAX_PWMS)
 		return -ENOSPC;
 
+	bitmap_set(allocated_pwms, start, count);
+
 	return start;
 }
 
@@ -297,8 +299,6 @@ int pwmchip_add(struct pwm_chip *chip)
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
 
-	bitmap_set(allocated_pwms, chip->base, chip->npwm);
-
 	INIT_LIST_HEAD(&chip->list);
 	list_add(&chip->list, &pwm_chips);